Of course it is possible that UFO's really do contain aliens as many people believe, and the government is hushing it up

If it [the universe] was expanding fairly slowly, the force of gravity would cause it eventually to stop expanding and then to start contracting. However, if it was expanding at more than a certain critical rate, gravity would never be strong enough to stop it, and the universe would continue to expand forever.

When something is made idiot proof, they will just make better idiots.

Issuing an insurance policy against abduction by aliens seems a pretty safe bet.

If we ever do find a complete theory of the universe, it would be a great triumph of human reason but it wouldn't leave much for us to do. We need an intellectual challenge.

Although September 11 was horrible, it didn't threaten the survival of the human race, like nuclear weapons do.

Because there is a law such as gravity, the Universe can and will create itself from nothing.